Method for producing improved motor fuels



Sept. 3o, 1,941.

P. AQMAscl-lwrrz METHQD FoR PRODUCINGMPROVED MoToRFUELs 2 sheets-sheet 1Original Filed Aug. 13, 1936A P. A. MASCHWITZ Sept. 30,' v1941.

' n mamon FoRl'PRoDUcING IMrRovE'D MOTOR FUELS original Filed Aug. 1s,-1936 2 sheets-sheet 2- Patented Sept. 30, 1941 METHOD FOR PRODUCINGIMPROVED MOTOR FUELS Percy A. Maschwtz, Toledo, Ohio, assignor to ThePure Oil Company, Chicago, lll., a corporation of Ohio Originalapplication August 13, 1936, Serial No. 95,745. Divided and thisapplication April 26, 1939, Serial No. 270,042

Claims.

This invention relates to method and `apparatus for producing highyields of high octane motor fuel from crude oil. More particularly theinvention resides in the combination of cracking, reforming, andpolymerizing in such manner that crude oil may be'subjected to acontinuous process in which the cracking stock, naphtha, and gases aretreated simultaneously in a unitary process to convert them into motorfuel.

This application is a division of my application Serial No. 95,745 filedAugust 13, 1936, now Patent No. 2,165,804..

In accordance with the invention, crude oil may be topped in the usualmanner to remove the gasoline, naphtha, and/or kerosene. The totaloverhead cut may be reformed at elevated temperatures and pressures oronly the heavier fraction thereof may be reformed. The topped crude maybe subjected to any suitable cracking operation in liquid, liquid-vapor,or vapor phase, and the resulting gasoline distillate combined with theproducts from the reforming operation. The combined products may be claytreated and fractionated to end point gasoline. The heavy ends separatedfrom the mixture may be recycled `to the cracking u nit.

TheV gases from the cracking and reforming operation may be intimatelycontacted with a portion or all the overhead fraction to be reformedunder elevated pressure in order to dissolve a portion of the gases. Thenaphtha enriched with the heavier gas fractions may be subjected toreforming, and the unabsorbed gases may be subjected to suitableconversion in ya separate still. The distillate produced in the gasconversion step may be combined with the cracked distillate and thereformed naphtha.`

The gas resulting from the gas conversion may be fractionated byabsorption to remove hydrogen, methane and other light gases, and theabsorbed constituents separated from the absorbent'and recycled to thegas conversion zone. A composite distillate of cracked gasoline,reformed naphtha, and .polymerized condensate is formed having anunusually high octane rating. The yield of gasoline is also higher thanhas heretofore been obtained for gasoline of equivalent knock rating.

The invention may be more clearly understood fromthe following detaileddescription considered in connection with the accompanymg drawhich:m'sigifrgl is a diagrammatic elevational view of apparaus forming partof the mvention and 1n which the method may be carrled out.

Figure 2 is a diagrammatic view of conventional apparatus for toppingand cracking crude oil.

Referring to the drawings, naphtha, gasoline, or kerosene may be chargedthrough line l by means of pump 3 either directlyinto the heating andreformingr coil 5 located in furnace 6, or through the line 'Icontrolled by valve 9. The naphtha, etc. may be obtained directly from atopping unit used in conjunction with the oil cracking process, or maybe obtained from a separate source. If desired, the charging stock maybe split into two streams by ,proper regulation of the v-alve 9 in line1 and the valve II in line I. From the line I the charging stock, whichis preferably heavy naphtha, passes into the top of an absorption towerI3 where it passes in counter-current contact with a stream of gases fedto the lower portion of the absorber throughA the line I5. The gases fedthrough line I5 may contain unsaturated hydrocarbons ranging in amountfrom 20-55%-. The absorption tower is preferably operated at a pressureof from 150-200 pounds per square inch and at a temperature of 100 F. orless.

Rich oil is withdrawn from the bottom of the absorption tower I3 throughline I1 by means of pump I9 and is charged through line I into theheating and reforming coil 5. The coil thus charged to the coil 5 willhave dissolved therein the heavier constituents of the gas, such asbutane, butylene and some propane and propylene. The rich oil may besubjected to pressures of 500-3000 pounds per square inch and totemperatures ranging from 800-1200 F. in the coil 5.

The products leaving the reforming coil 5 pass into arrester 2| Wherethey are contacted with cool oil withdrawn from the gas separator 23through line 25 by means of pump 21. The re- 4actlon products arechilled in the arrester 2I to a temperature below 700 F. and preferablyto a temperature .between 500 and 600 F. The partially cooled reactionproducts pass through line 29 controlled by valve 30 to the upperportion 0f a chamber 3l containing a bed of fullers earth or other claycapable of functioning :as an adsorptive catalyst. The clay lchamber maybe maintained under substantially reaction pressure or the pressure mayVbe reduced somewhat by means of the valve 30 before the products enterthe clay chamber. In the clay chamber the unstable gum-forming andcolor-imparting bodiesV undergo polymerization to heavier bodies. Thecombined reaction products are withdr-awn from the bottom of the claychamber through line 33 controlledby valve 35 and pass into the lowerportion of fractionating tower 31. The pressure on the products may bereduced to vapproximately 150-200 pounds per square inch or lower beforeentering thefractionating tower'. Ifnecessary, the products leaving theclaychamber maybe preheated prior to passing into the fractionatingtower.

gasoline range takes place, and these vapors pass Y overhead throughline 39 while the heavier ends and polymers formed in the clay chamberand in the reforming coil 5, may be withdrawn. through the line 4|controlled by valve 43. `Open steam may be used in tower 31 and insubsequent frac.

In the fractionating tower 31, vapor'-, Y ization of the lighter vapors-boiling within the..A

tionating towers to assist in .separating r4lightlV ends from theunvaporized portions.V When open steam is used, suitable provisionshouldbe made for drawing off water from the separators following thefractionating towers. The higher boiling materials withdrawn throughline lll may Y be recycled to an oil cracking unit, such as a vaporphase unitormay.be withdrawnfrom the system(l It is Vapparent .that theheavy boiling liquid vwithdrawnthrough the line 4| maybe in partwithdrawn from the system andinpart recycled to an oil cracking system.Y f

The vapors and gases Withdrawn through'line 39'pass through thecondenser Ll5 where the tem- Apera'ture of thefproducts is lowered toapproxi- 3 Vmately',100"l1. or less and then through line 41 into,accumulator 49;4 The condensate collected in accumulator llfm'ay be inVpart withdrawn thro1 igh. .line5|` by means of pump 53 and recycledtothe upper portion of the fractionating tower.las` refluxl; Theremaining portion of the condensate -may be withdrawn from the bottornrof the accumulator 49 through line 5'5Y controlled by valveY 51, intoaccumulator 59.

Uncondensedgase's leave the top of the ac-` l cumulatorltfl through line5|,l`pass through cooler A63v where the temperature is further reduced,ifnecessary,rto or below 100 F., and are then charged through line 61into accumulator 59. r `C ias leaving the top of gas separator 23through p line maybe-compressed by compressor 13 to a pressure lofapproximately 150-2Q0 pounds per j square inchY and charged intoaccumulator59 together Withrthe gases-"from accumulator 49. Then-gasesfromrrthe Ygas separator 23 may result from thecracking of topped crudeor other oil in a cracking process, of the liquid, liquid-vapor, or

`vapor phase type. The'combined gasesrand gas- Vi oline distillatewfromthe cracking unit may pass through line 15, after having been cooled toaY [temperature suiiicient to condense the vapors 1V boilingfwithin thegasoline rangeinto the gas v I separator. 23V wherel the gas separatesfrom the condensate.

Uncondensed gases leave the top of the accu-v AnyV liquids abilizer-v`isequipped with bubble tent of the gases.

ed to a temperature sufficient to vaporize those 1 constituents such aspropylene, butylene, propane and butane, which are undesirable, ingasoline. These vapors and gases return from the reboiler to thestabilizer through line 89. The

unvaporized portions are withdrawn from the.v

reboiler through line 9| and may be charged to the storage tank 92through line 93 controlled ',by' valve 94, or may be withdrawn toseparate loV Y ,'Uncondensed` gases leave the stabilizer through lineIUI, pass through condenser |93` storage through line 91 controlled byvalve 99. 83

intofaccumulator |05. Any condensate which forms in the laccumulator mayvbe recycled Y through line'l'l by means of pump |09 to the top of thestabilizer, as reflux. The uncondensed4 gases rleave the top of theaccumulator |05 through line HI, pass through cooler H3, whereYthetemperature is reduced to 100 F. or less, and join the gases fromline 11 passing into the absorber I3. I

Unabsorbed gases' leave the top of the absorber i3 through vline ||5 andare charged by means of compressor. H1 to the heating coil ||9,loc`atedin furnace |2|. Thegases may be'heated to a temperatureA ranging from800'140`O F. in the coil |`9 yundergpressures of from 10U-3000 poundsper square inch. The pressure used'will depend upon theVtemperatureftowhich the gases are heated. At higher temperatures, thepressure will be correspondingly lower, while at lower temperatures,higher pressures will be used.

The temperature to which tli'egases are heated.

will depend to alarge extent on the olenicrcon- 30% 'olenic content, itislpreferable to use tem- 120025K are preferable. l The heated gasesleave coil i9 through line |23 controlled by valve |25 peratures ofW-1400""v F. in yordervr to obtain substantialncracking together l,withpolymerization; When theolenic content ofthe gasesexfY ceedsapproximately 30%, temperaturesV below andmay be either passed throughreaction zone |21 or may be by-passed around thev reaction zonethroughline |29 controlled by valve 13|'. The reaction zone |21 may.take either the form of an enlarged coil or .an enlarged reactionvcharnber preferably heat insulated.v Iflthe products are subjectedtohigh/pressure treatment, it may be desirable Vtofuse the reaction zione,but'where high temperaturesand low4 pressures are used with consequentshort reaction periods, it may be desirable toby-pa'sstherreaction zone.'I "Vhe' particular, conditions of temperature and pressure and theperiod of reaction desired will de-- termine whether or not the reactionzone will Y be` utilized*r lheqproducts leaving the' reaction zone |21.or .the heating coil H9, as thecase may be, pass through line `|33co'ntrolled'fby valve .|35 into thetlower portionfof.evaporator |31.11n-Y mediately after leaving the reaction zone Yor thef-V heating cOil,the products are.''quikzlrly` chilled Yto a temperature of 600- F. orlower by means'of contact with cool oil withdrawnfrom gas sepa` rator|39 through'line' |4| by means of pump |43. A portion-ofthe.oil"fromftheline lfll'rn'ay; Y be charged into the -upperpor'tion ofEthelevapo#vrator |31 through line lll'icontrolledfby Valve |41 toractas-reflux. Thepressureof the prod-VV ucts entering' the v,evaporator isVpreferablyfire-Y Y Y, ducedv v ,tov -approximately v175-`225 poundsVVper Y f square inch. Tarry constituents'are knockedl'out andwithdrawnV from'the bottom oflthe evapoy rater Athrough line--l9fcontrolled by'valve'ISl and may bereitlrer recycled tothe oil,cracking- With'gases of less" than about` step or withdrawn from thesystem. The remaining vapors and gases pass over the top of theevaporator through line |53, condenser |55 and line |51. intoaccumulator 59.

Condensate may be withdrawn from the accumulator |59 through line |6|and charged to the gas separator |39. Uncondensed gases from theaccumulator |59 are withdrawn from the top thereof through line |62controlled by valve |63 and may be charged through line |64 controlledby valve |65 to the lower portion of absorption tower |61. When the gasconversion system is operated under low pressure, it may be necessary tocompress the gases leaving accumulator |59, by means of compressor |58,prior to delivery to the absorber. Absorption oil, which may be heavynaphtha, mineral seal or gas oil, may be charged into the upper portionof the absorber through line |69 and passed in counter-current Contactwith the gases charged to the absorber through line il. The unabsorbedgases leave the top of the absorber through line |1| controlled by valve|13 and may be withdrawn from the system. The rich absorber oil may bewithdrawn from the bottom of the absorber through line |15, passedthrough heat exchanger |11, line |19 controlled by valve |36) and heater|8l, into an intermediate portion of the still |83. The absorbed gasesand light vapors are stripped from the absorber oil and pass off the topof the still through line |85, through condenser |21, into the gasseparator |39 where the condensed vapors mix with the condensate fromthe accumulator |59. A part of the condensate from the separator |39 maybe returned from the bottom thereof through line |89 by means of pump|95 to the top of the still |83, as reflux. As previously stated, aportion of this condensate may be used as chilling fluid for theproducts leaving the polymerization zone. The remaining condensate iswithdrawn from separator it@ through line |93 y and may either becharged by means of pump |94 to the gas separator 23 where it iscombined with the cracked light distillate to undergo clay treatment andfinal fractionation, or may be withdrawn from the system through line|95 controlled by valve H1 and separately collected. Uncondensed gas maybe taken off the top of separator |39 and recycled to the inlet of coil||9 through line |28.

The denuded absorber oil is withdrawn from the bottom of the still |53by means of pump IM through line 299, heat exchanger |11, where it givesup a portion of its heat to the rich oil, and then charged through line|@9 and cooler 263| into the top of the absorber. Makeup oil may beadded to the line |69 as required through line 203 controlled by valve255. The absorber |61' is preferably maintained under a pressure of 175-225 pounds per square inch and at a temperature of approximately 100 F.or less. The still E83 and gas separator |39 are preferably maintainedunder pressure of 15G-200 pounds per square inch, but may be maintainedat lower pressures when polymerization is carried out at low pressures.

It will be apparent that instead of utilizing separate absorption andstripping means for the uncondensed gases from the accumulator |59, theuncondensed gases therefrom may be recycled in whole or in part to theabsorber I3 through line 2131 controlled by valve 299. In order to dothis it merely is necessary to close valves it in line |64 and to openthe valve 209 in line Ztl. When operating in this manner excess gas maybe removed from the system through line 2li controlled by valve 2 3.

Referring to Figure 2, crude oil is pumped by means of pump 220 throughline 222 into heating coil 224. In the coil 224 the oil is heatedsufficiently to vaporize the oil but not to crack it. From the heatingcoil the oil passes into the fractionating tower 226. Gasoline iswithdrawn overhead as a vapor through line 22B and passed throughcondenser 23|) into separator 232 from which it may be withdrawn throughline 234 controlled by valve 23B.

Heavy naphtha containing or not containing kerosene, may be withdrawnfrom an intermediate portion of the fractionator 226 through line 238.Line 234 is connected to line 23S by line 240 controlled by valve 242 sothat topped gasoline may be mixed with heavy naphtha if desire-d priorto charging the latter through line l to the reforming coil.

Cracking stock may be withdrawn from the lower portion of the towerthrough line 2M controlled by valve 2% and charged by means of pump 243through heating and cracking coil 250. From the cracking coil thereaction products may pass into evaporator 252. The vapors pass overheadfrom the evaporator through line 254 controlled by valve 25S intofractionating tower 253. Gasoline and gases are taken overhead from thefractionating tower through line 26|] controlled by valve 262 intocooling and condensing coil 25d. From the coil 2M the mixed gases andgasoline pass 'through line 15 to separator 23.

From the foregoing description it will be seen that a system has beenprovided for treating crude oil whereby the oil may be first topped andthe natural gasoline fraction obtained from the topping operation or aheavy fraction thereof reformed either alone or in conjunction withconversion of hydrocarbon gases obtained from the cracking and reformingsteps. The system further provides for conversion of the lighterportions of the gases under any desired conditions in order to producetherefrom either aromatic hydrocarbons or other liquid hydrocarbonsboiling within the gasoline range, and for clay treatment andfractionation of the combined gasoline boiling range products to producea motor fuel of high anti-knock characteristics,

The process provides a flexible means for treating hydrocarbon gases toproduce therefrom motor fuel hydrocarbons boiling within the gasolinerange. By absorbing the heavier gas constituents in the naphtha which isto be reformed, the necessity for separate conversion of these gases isavoided and at the same time means is provided for charging these gasesin the liquid state to a conversion zone. The light portions of thegases, which cannot be absorbed,

can be polymerized separately under conditions which are suitable to theolenic content thereof. Moreover, the character of liquid products whichmay be obtained from the light gases can be regulated at will byindependent control of the temperatures and pressures to which they aresubjected. If it is not desired to make preponderantly aromatichydrocarbons, high pressure conditions and lower temperatures may beused and larger yields of liquid products thereby obtained. Where theprimary object is to obtain aromatic hydrocarbons from the light gaseousportions, higher temperatures and lower pressures may be utilized.

By subjecting the heavier and higher olenic gas fraction to conversionabsorbed in naphtha,

knock value can be obtained. Apparently poly- `merization and alkylationtake place simultaneously so that saturated aswell as unsaturatedhydrocarbons take part inthe reaction. The light unabsorbed fraction, onthe other hand, is relatively lean in oleiinic content and requires moreseverek treatment than the absorbed gases. By adjusting the pressure andtemperature conditions in absorber I3 in accordance with the compositionof the gas fed to it, the gas can be fractionated to yield two fractionsmost suitable for the particular conditions of reaction to which theyare subjected and increased yields thereby obtained.

Although a specific method of cracking, reforming and polymerizing, hasbeen shown and described, it is to be understood that the invention isnot limited to the specific form shown and described, but coversbroadlyprocess and apparatus for combining the steps of cracking,

Y reforming and gas polymerization in a unitary process. Furthermore,although the invention has been described as being applicable totreatment of crude oil, it is apparent that oil, naphtha, and gases fromseparate sources may be utilized.

I claim: Y l. A Yprocess for theV treatment of hydrocarbon oils whichcomprises fractionally distilling an `Voil of relatively wide boilingrange and thereby separating it into W boiling and high boilingfractions, supplying high boiling fractions to a cracking operation,supplying low boiling fractions .ofthe charging oil, Which comprise at.

least a substantialV quantity of poor anti-knock V*gasoline fractions,to a heating coil separate from said cracking operation and thereinheatingk the v same under cracking conditions of elevated temperaturevand superatmospheric pressure regulated to effect a materialimprovement in the anti-knock value of said gasoline fractions,discharging resultant highly heated productsfrom the heating coil,partially cooling the samev sufliciently to prevent any-excessivefurther cracking thereof, separating'gases and gasoline boilingconstituents from the partially lcooled products, returning fractionsboiling above the gasoline range to said rst mentioned vcracking,operation, subjecting the mixed gasoline Y'vapors and gases ktocondensation, separatingY the resulting condensate -from uncondensedgases, stabilizingthe resulting condensate l to reduce its ,vaporVpressure to the desired degree by separating therefrom normally gaseouscon-` stituents dissolved'therein, supplying gases produced in saidfirst mentioned cracking operation and thoseV resulting from thecracking of the loW boiling fractions to an absorber,l contacting saidgases in said absorber with an absorber oil comprising loW boilingfractions of the charging oil and'thereby dissolving the heavierconstitut Yents of the gases,vand supplying the resultingv enrichedabsorber oil to said heating coil.

Y 2. Process in accordance with claim l'vvhere gases undissolved by theabsorber oil are not returned toY either the cracking` operation or theheating coil.V

3. A process for the treatment of hydrocarbon 70 oils Whichcornprisesfractionally distilling an oil of relatively. wide boiling range andthereby separating itrinto loW boiling and high boiling n. fractions,supplying high boiling fractions to a Ycracking operation, supplying lowboiling fracing the same under cracking conditions fofelevatedtemperature and superatmospheric pressure regulated to effect a materialimprovement in the anti-knock value of 'said gasoline fractions,discharging resultant highly heated products from the heating coil,partially cooling the same by heat exchange relation with relativelycooler products from the first mentioned cracking operation to atemperature suiiiciently low to prevent further cracking thereof, sepa-`rating gases and gasoline boiling constituents from the resultantpartially cooled products, returning fractions boiling above thegasoline range to said first mentioned cracking operation, subjectingthe mixed gasoline vapors and gases to condensation, separating theresulting condensate frompuncondensed gases, stabilizing the resultingcondensate to reduce itsV vapor pressure to the desired degree byseparating therefrom normally gaseous constituents dissolved therein,supplying gases produced in said rst mentioned cracking operationandthose resulting from the cracking of the low boiling fractions to anabsorber, Vcontacting said gases in said absorber with an absorber oilcomprising low boiling fractions of the charging oil thereby separatinghigh boiling components'of the gases from loW boiling components thereofby absorption of the former and supplying the resulting enrichedabsorber oil to said heating coil. Y

4. A process for the treatment of hydrocarbon oils which comprisesfractionally distilling Van oil of relatively Wide boiling range andthereby separating it into low boiling and high boiling fractions,supplying high boiling fractions to Va cracking operation, supplying lowboiling fractions ofthe charging oil, which comprise at leastY asubstantial quantity of poor anti-knock gasoline fractions, to a heatingcoil separate from said cracking operation and therein heating the sameunder cracking conditions of elevated temperature and superatmosphericpressure regu- Vlated to effect a material improvement in the anti-knockvalue of said gasoline fractions, discharging resultant highly heatedproducts from densate to reduce its vaporpressure to the de- 1 sireddegree by Ysep-arating therefrom normally gaseous constituentsdissolvedtherein, supplying gases produced in said' rstrnentioned crackingoperation and those resultingfrom the crackingV of the low boilingfractions to an absorber, contacting said gases in said absorber withabsorber oil suitable for cracking into motor fuelboiling rangecomponents, thereby separating desirable u high boiling components ofthe gases froml low boiling components thereofzby .absorption of theformer and supplying the resultingv enrichedY absorber oil Yto saidheating coil. Y

, 5. A processY for the treatment of hydrocarbon oils which comprisesfractionally distilling an oil of relatively Wide boiling range andthereby sparating it into low boiling and high boiling fractions,supplying high boiling fractions to a cracking operation, supplying lowboilingfractions of 'the charging oil, which comprise at least asubstantial quantity of poor anti-knock gasoline fractions, to a heatingcoil separate from said cracking operation and therein heating the sameunder cracking conditions of elevated temperature and superatmosphericpressure regulated to effect a materialimprovement in the anti-knockvalue of said'r gasoline fractions, discharging resultant highly heatedproducts from the heating coil, cooling the same sufliciently to preventany excessive further cracking thereof, separating gases and gasolineboiling cons-tituents from the partially cooled products, returningfractions boiling above the gasoline range for further cracking,subjecting the mixed gasoline vapors vand gases tocondensation,separating the resulting condensate from uncondensed gases,stabilizing the resulting condensate to reduce its vapor pressure to thedesired degree by separating therefrom normally gaseous constituentsdissolved therein, supplying gases produced in said rst mentionedcracking operation and those resulting from the cracking of the lowboiling fractions to an absorber, contacting said gases in said absorberwith an absorber oil comprising low boiling fractions of the chargingoil, thereby dissolving the heavier constituents of the gases, andsupplying the resulting enriched absorber oil to said heating coil.

6. A process for the treatment of hydrocarbon oils which comprisesfractionally distilling an oil of relatively Wide boiling range andthereby separating it into low boiling and high boiling fractions,supplying high boiling fractions to a cracking operation, supplying lowboiling fractions of the charging oil, which comprise at least asubstantial quantity of poor anti-knock gasoline fractions, to a heatingcoil separate from said cracking operation and therein heating the sameunder cracking conditions of elevated temperature and superatmosphericpressure regulated to effect a material improvement in the anti-knockvalue of said gasoline fractions, discharging resultant highly heatedproducts from the heating coil, partially cooling the same sufficientlyto prevent excessive further cracking thereof by passing said highlyheated products in direct heat exchange relationship with relativelycooler fractions from said first mentioned cracking operation,separating gases and gasoline boiling constituents from the partiallycooled products, returning fractions boiling above the gasoline range tosaid first mentioned cracking operation, subjecting the mixed gasolinevapors and gases to condensation, separating the resulting condensatefrom uncondensed gases, stabilizing the resulting condensate to reduceits vapor pressure to the desired degree by separating therefromnormally gaseous constituents dissolved therein, supplying gasesproduced in said first mentioned cracking operation and those resultingfrom the cracking of the low boiling fractions to an absorber,contacting said gases in said absorber with an absorber oil comprisinglow boiling fractions of the charging oil and thereby dissolving theheavier constituents of the gases, and supplyingr the resulting enrichedabsorber oil to said heating coil.

7. A process for the treatment of hydrocarbon oils Which comprisesfractionally distilling an oil of relatively Wide boiling range andthereby separating it into low boiling and high boiling fractions,supplying high boiling fractions to a cracking operation, supplying lowboiling fractions of the charging oil, which comprise at least asubstantial quantity of poor anti-knock gasoline fractions, to a heatingcoil separate from said cracking operation and therein heating the sameunder cracking conditions of elevated vternperature and superatmosphericpressure regulated to effect a material improvement in the anti-knockvalue of said gasoline fractions, discharging resultant highly heatedproducts from the heating coil, cooling the vsame sufficiently toprevent any excessive further cracking thereof, separating gases andgasoline boiling constituents from the kpartially cooled products,returning fractions boiling above the gasoline range to said firstmentioned cracking operation, subjecting the mixed gasoline vapors andgases to condensation, separating the resulting condensate fromuncondensed gases, stabilizing `the resulting condensate to reduce itsvapor pressure to the desired degree by separating therefrom normallygaseous constituents dissolved therein, combining said uncondensed gasesand said normally gaseous constituents with gases produced in said firstmentioned cracking operation and supplying the combined gases to anabsorber, contacting said gases in said absorber with an absorber oilcomprising loW boiling fractions of the charging oil and therebydissolving the heavier constituents of the gases, and supplying theresulting enriched absorber oil to said heating coil.

8, A process for the treatment of hydrocarbon oils Which comprisesfractionally distilling an oil of relatively Wide boiling range andthereby separating it into low boiling and high boiling fractions,supplying high boiling fractions to a crackng operation, supplying loWboiling fractions of the charging oil, which comprise at least asubstantial quantity of poor anti-knock gasoline fractions, to a heatingcoil separate from said cracking operation and therein heating the sameunder cracking conditions of elevated temperature and superatmosphericpressure regulated to effect a material improvement in the anti-knockvalue of said gasoline fractions, discharging resultant highly heatedproducts from the heating coil, cooling the same sufficiently to preventany excessive further cracking thereof, separating gases and gasolineboiling constituents from the partially cooled products, returningfractions boiling above the gasoline range to said first mentionedcracking operation, subjecting the mixed gasoline vapors and gases tocondensation, separating the resulting condensate from uncondensedgases, stabilizing the resulting condensate to reduce its vapor pressureto the desired degree by separating therefrom normally gaseousconstituents dissolved therein, combining said uncondensed gases andsaid normally gaseous constituents With gases produced in said firstmentioned cracking operation and supplying the combined gases to anabsorber, contacting said gases in said absorber with absorber oilsuitable for cracking into motor fuel boiling range hydrocarbons therebydissolving the heavier constituents of the gases and supplying theresulting enriched absorber oil to said heating coil.

9. Process in accordance with claim 8 Where gases undissolved by theabsorber oil are not returned to either the cracking operation or theheating coil.

10. A process for the treatment of hydrocarbon oils which comprisesfractionally distilling an oil of relatively Wide boiling range andthereby separating the samel into relatively loW boiling and highboiling fractions, supplying high boiling fractions to a crackingoperation, supplyinglow boiling fractions of the charging oil, whichcomprise at least a substantial quantity of poor anti-knock gasolinefractions, to a heating coil and therein heating the same under crackingconditions of elevated temperature and superatmospheric pressureregulated to effect a `material improvement in the anti-knock Value ofsaid gasoline fractions, `discharging resultant nentsrboilingv above therang-e of gasoline including reflux condensate formed by said frac- Ytionation to the rst mentioned cracking operation for further cracking,subjecting the fractionated vapors of vv the desired end boiling pointto condensation,` separating the resulting distillate and uncondensedgases, stabilizing the distillate to reduce its vapor pressure to thedesired degree by liberating dissolved normally gaseous productstherefrom, supplying gases liberated from the distillate by'saidstabilization to an` absorber, therein contacting the Same With anabsorber oil comprising 10W boiling fractions of the charging oil andthereby separating desirable high boiling components of the gases,including readily polymerizable olens, from the lower boiling componentsthereof, byabsorption of the former, and supplying the resultingenriched absorber oil to said heating coil.

PERCY A. MASCHWITZ.

